Method of manufacturing conductive particle, anisotropic conductive adhesive having the same, and method of manufacturing display apparatus using the same

ABSTRACT

In an anisotropic conductive adhesive containing a conductive particle, the conductive particle includes a resin particle that is provided with a cavity formed therein and a conductive layer surrounding a surface of the resin particle. The cavity is formed by mixing the resin particle with a reactant and partially removing the reactant from the resin particle. Thus, the conductive particle may readily absorb an external pressure, thereby providing an improved malleability to the conductive particle.

This application claims priority to Korean Patent Application No.2007-92218, filed on Sep. 11, 2007, and all the benefits accruingtherefrom under 35 U.S.C. §119, the contents of which in its entiretyare hereby incorporated by reference.

BACKGROUND OF THE INVENTION

This disclosure relates to a method of manufacturing a conductiveparticle, an anisotropic conductive adhesive having the conductiveparticle, and a method of manufacturing a display apparatus using theanisotropic conductive adhesive.

For purposes of mounting a driver integrated circuit on a display panel,chip-on-glass (COG) methods and tape-automated-bonding (TAB) methodshave been widely used. According to the COG method, a driver integratedcircuit is directly mounted on the display panel without using aseparate structure. In the TAB method, a driver integrated circuit isindirectly connected to the display panel through a tape carrier packageor a film (chip-on-film), where the driver integrated circuit ismounted.

In this method, the tape carrier package or the chip-on-film, on which adriver integrated circuit is mounted, serves as a signal transmissionmember and is electrically connected to the display panel through ananisotropic conductive film (ACF). The ACF is also applied when thesignal transmission member is bonded to a printed circuit board on whicha driving circuit is printed.

In order to electrically connect the signal transmission member to thedisplay panel, an ACF containing conductive particles is disposedbetween terminals formed on the signal transmission member and terminalsformed on the display panel. Then, heat and pressure is applied to theACF such that the conductive particles contained therein are compressedand make contact with the terminals of the signal transmission memberand display panel, thereby electrically connecting the signaltransmission member and the display panel with each other.

BRIEF SUMMARY OF THE INVENTION

Disclosed is a method of manufacturing a conductive particle. A resin ismixed with a first reactant to form a particle, and the first reactantis removed from the particle using a second reactant to form a cavity inthe particle. Then, the particle is heat-treated to reduce the volume ofthe cavity, and then a conductive layer is formed to surround theparticle.

Further disclosed is a method of manufacturing a display apparatus. Adisplay panel on which a first terminal is formed and a driver on whicha second terminal is formed are prepared. An anisotropic conductiveadhesive having the above-described conductive particle is formed on atleast one of the first terminal and the second terminal. Then, the firstterminal and the second terminal are positioned to face each other withthe anisotropic conductive adhesive interposed between the first andsecond terminals, and the first and second terminals are compressed tobe electrically connected to each other through the conductive particle.

Further disclosed is an anisotropic conductive adhesive including anadhesive and the above-mentioned conductive particle dispersed in theadhesive. The conductive particle includes a particle having a cavityformed therein and a conductive layer surrounding the particle.

The conductive particle contained in the anisotropic conductive adhesiveis provided with the cavity and thus the conductive particle can readilyabsorb an external pressure, thereby enabling to provide an improvedmalleability to the entire anisotropic conductive adhesive.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and advantages of the disclosed embodimentswill become readily apparent by the following detailed description whenconsidered in conjunction with the accompanying drawings, wherein:

FIG. 1 is a flowchart illustrating a method of manufacturing aconductive particle according to an exemplary embodiment of the presentinvention;

FIGS. 2 to 6 illustrate steps of manufacturing a conductive particleaccording to an exemplary embodiment of the present invention;

FIG. 7A is a sectional view of a primary resin particle shown in FIG. 4;

FIG. 7B is an enlarged view for the portion A in FIG. 7A;

FIG. 7C is an enlarged view for the portion B in FIG. 7A;

FIG. 8A is a sectional view for the resin particle shown in FIG. 5;

FIG. 8B is an enlarged view for the portion C in FIG. 8A;

FIG. 9 is a perspective view for the conductive particle shown in FIG.6;

FIG. 10 is a perspective view showing a liquid crystal display accordingto an exemplary embodiment of the present invention;

FIG. 11 is a sectional view taken along the line I-I′ of FIG. 10; and

FIGS. 12A and 12B are enlarged views for the portion where a liquidcrystal display panel and a gate driver are bonded to each other.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Disclosed embodiments will now be described more fully with reference tothe accompanying drawings, in which exemplary embodiments are shown.

It will be understood that when an element or layer is referred to asbeing “on”, “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. Like numbers refer to likeelements throughout. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer or section fromanother region, layer or section. Thus, a first element, component,region, layer or section discussed below could be termed a secondelement, component, region, layer or section without departing from theteachings of the present invention.

Terms denoting spatial inter-relationships, such as “beneath”, “below”,“lower”, “above”, “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation in addition tothe orientation depicted in the figures. For example, if the device inthe figures is turned over, elements described as “below” or “beneath”other elements or features would then be oriented “above” the otherelements or features. Thus, the exemplary term “below” can encompassboth an orientation of above and below. The device may be otherwiseoriented (rotated 90 degrees or at other orientations) and the spatiallyrelative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms, “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “includes”and/or “including”, when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

In the drawings, like reference numerals denote like elements and thethicknesses of layers and regions are exaggerated for clarity.

FIG. 1 is a flowchart illustrating a method of manufacturing aconductive particle according to an exemplary embodiment, and FIGS. 2 to6 illustrate steps of manufacturing a conductive particle according toan exemplary embodiment.

Referring to FIG. 1, the formation of a conductive particle includesconverting the surface of a reactant into a hydrophobic state (S10),forming a mixture by mixing the reactant with a resin (S20), forming aresin particle using the mixture (S30), removing the reactant from theresin particle by reacting the resin particle with a solvent (S40),heat-treating the resin particle (S50), and forming a metal layer on thesurface of the resin particle (S60).

In step S40, as the reactant is removed from the resin particle by thesolvent, cavities are formed on the surface of the resin particle andalso inside the resin particle. In step S50, while the resin particle isheat-treated, the volume of the cavities is reduced, so that fineconcave portions are formed on the surface of the resin particle. Sincethe fine concave portions are randomly formed on the surface of theresin particle, the fine concave portions may appear to be wrinkles.Further details on the conductive particle will be described hereinafterwith reference to FIGS. 2 to 6.

Referring to FIG. 2, the reactant 30 is contained in a container 5.Then, a first surface treating agent 10 and a second surface treatingagent 20 are supplied into the container 5 such that the reactant 30,the first surface treating agent 10, and the second surface treatingagent 20 are reacted with each other to form a hydrophobic reactant 31(see FIG. 3).

When the reactant 30 comprises calcium carbonate (CaCO₃) and the secondsurface treating agent 20 comprises the stearic acid, a surfacetreatment following below chemical reaction formula is performedrelative to the surface of the reactant 30.

CaCO₃+RCOOH->Ca(OH)(OOCR)+CO₂  <Chemical Reaction Formula>

A contact angle between the reactant 30 and water may be approximately48° when the surface treatment is performed relative to 25 percent ofthe surface of the reactant 30, the contact angle between the reactant30 and water may be greater than 100° when the surface treatment isperformed relative to 50 percent of the surface of the reactant 30.Accordingly, when the surface treatment is performed gradually, thesurface of the reactant 30 is made the hydrophobic gradually. Here, thesurface of the reactant is made hydrophobic by the first and secondsurface treating agents 10 and 20. Thereafter, as shown in FIG. 3, thehydrophobic reactant 31 is mixed with a resin 40 such that thehydrophobic reactant 31 is uniformly dispersed in the resin 40.

In this embodiment, the reactant 30 includes calcium carbonate (CaCO₃),the first surface treating agent 10 includes ethanol, and the secondsurface treating agent 20 includes stearic acid. The reactant 30, thefirst surface treating agent 10 and the second surface treating agent 20have a mass ratio of 1:10:0.4.

In the present exemplary embodiment, the reactant 30 includes calciumcarbonate (CaCO₃), but the reactant 30 may include various othermaterials such as so long as they do not react with the resin. This isbecause the reactant 30 is to be removed from the mixture of thereactant 30 and the resin 40 in a subsequent process.

Referring to FIG. 3, the hydrophobic reactant 31 and the resin 40 aremixed and contained in the container 5. That is, the hydrophobicreactant 31 is mixed with the resin 40 to form a mixture of the resin 40and the hydrophobic reactant 31 uniformly dispersed in the resin. Thismixture serves as a particle raw material 44 to form a primary resinparticle.

Referring to FIGS. 4 and 5, a primary resin particle 45 having aspherical shape is formed using the particle raw material 44. Theprimary resin particle 45 may be formed from the particle raw material44 using polymerization, such as a seeded polymerization, a suspensionpolymerization, an emulsion polymerization, and a dispersionpolymerization. For example, the suspension polymerization (also knownas pearl polymerization, bead polymerization and granularpolymerization) is a polymerization process that uses mechanicalagitation to mix the monomer or mixture of monomers in a liquid phasesuch as water, polymerizing the monomer droplets while they aredispersed by continuous agitation.

Then, the primary resin particle 45 is reacted with a solvent 60 suchthat the solvent 60 dissolves the hydrophobic reactant 31 out from theprevious resin particle 45. As the result, first cavities 34 are formedin the primary resin particle 45, as shown in FIG. 7B. The volume of thefirst cavities 34 amounts substantially to the volume of the hydrophobicreactant 31 that has been dissolved out by the solvent 60.

Since the hydrophobic reactant 31 is calcium carbonate in thisembodiment, the solvent 60 may include a hydrochloric acid aqueoussolution that can dissolve the calcium carbonate. In this case, in orderfor the solvent 60, i.e. the hydrochloric acid aqueous solution not toreact with the resin substance of the primary resin particle 45, thehydrochloric acid aqueous solution may be diluted at 0.1 mol/L.

Then, the primary resin particle 45 having the first cavities 34 isheat-treated at a temperature of about 220 degrees Celsius for one hourto form a secondary resin particle 50. While heat-treating the primaryresin particle 45, the volumes of the first cavities 34 formed in theprimary resin particle 45 are reduced, thereby forming fine concaveportions on the surface of the secondary resin particle 50.

Since massive first cavities 34 are randomly formed in the primary resinparticle 45, the fine concave portions are also formed so as to berandomly distributed over the surface of the secondary resin particle50. Consequently, the fine concave portions may appear to be wrinklesdefined on the surface of the resin particle 50.

The primary previous resin particle 45 and secondary resin particle 50will be described in further details with reference to FIGS. 7A to 7Cand FIGS. 8A and 8B respectively.

Referring to FIG. 6, the secondary resin particle 50 is reacted with aplating solution 95 to form a conductive layer 70 on the surface of thesecondary resin particle 50 and consequently form a conductive particle100 with the conductive layer 70 covered on the surface thereof.

In this exemplary embodiment, the conductive layer 70 may be formed of ametallic material such as nickel, gold, and the like through aconventional plating process. Also, the conductive layer 70 isillustrated to have a single-layer structure, but the conductive layermay have two or more layered structure.

FIG. 7A is a sectional view for the primary resin particle shown in FIG.4, FIG. 7B is an enlarged view for the portion A of FIG. 7A, and FIG. 7Cis an enlarged view for the portion B of FIG. 7A. More particularly,FIG. 7B shows the surface of the primary resin particle 45 in detail,and FIG. 7C shows the first cavities and the un-removed hydrophobicreactant in detail.

Referring to FIGS. 7A to 7C, the first cavities 34 are partially formedin the primary resin particle 45, mainly over the area near the surfaceof the particle. Specifically, it is assumed, as shown in FIG. 8A, thatthe primary resin particle 45 is defined as a sphere (A) having a firstradius d1 and an imaginary sphere (B) having a second radius d2 isformed inside of the sphere (A), the both spheres having a common centerpoint CP. Then, the first cavities 34 are considered to be formed in theregion outside of the imaginary sphere (B). In other words, the firstcavities 34 are formed spaced apart from the point CP to surround theimaginary sphere (B).

In this embodiment, the solvent 60 removes the hydrophobic reactant 31inwardly adjacent to the surface of the primary resin particle 45. Thisis, the hydrophobic reactant 31 adjacent to the surface of the primaryresin particle 45 is removed first, rather than the hydrophobic reactant31 adjacent to the inner portion of the primary resin particle 45. Inother words, the solvent 60 is diffused from the surface of the primaryresin particle 45 toward the center portion of the primary resinparticle 45 while removing the hydrophobic reactant 31. Thus, by varyingthe reaction time of the primary resin particle 45 with the solvent 60,the numbers and boundary of the first cavities 34 being formed insidethe primary resin particle 45 can be adjusted, thereby controlling themalleability of the later-formed conductive particle 100.

For instance, when the primary resin particles 45 having a diameter ofabout 4 micrometers remain in contact with the solvent 60 for fewminutes, the hydrophobic reactant 31 is removed from the surface of theprimary resin particle 45 up to a depth of about 0.4 micrometers, whichcorresponds to 10 percents (i.e., 0.1 times) of the diameter of theprimary resin particle 45. As the number of the first cavities 34 formedin the primary resin particle 45 increases, the malleability of thesubsequently formed conductive particle 100 containing the primary resinparticle 45 increases. For example, as described above, if the firstcavities 34 is formed up to about 0.4 micrometers inwards of the surfaceof the primary resin particle having a diameter of 4 micrometers, themalleability can be improved by about 10 percents, as compared with aconductive particle produced from a primary resin particle not formedwith the first cavities.

Although the first cavities 34 are formed on the surface 47 of theprimary resin particle 45, the surface 47 of the primary resin particle45 is substantially flat except for the concave portions caused by thefirst cavities 34. This is because the solvent 60 is not reacted withthe resin 40, as is shown in FIG. 7B.

FIG. 8A is a sectional view for the resin particle shown in FIG. 5, andFIG. 8B is an enlarged view for the portion C in FIG. 8A. Particularly,FIG. 8B shows detailed configurations for the surface of the resinparticle shown in FIG. 8A.

Referring to FIGS. 8A and 8B, second cavities 35 are partially formed inthe secondary resin particle 50 after the heat-treatment. Morespecifically, it is assumed, as shown in FIG. 8A, that the secondaryresin particle 50 is defined as a sphere having a first radius d1 and animaginary sphere having a second radius d2 is formed inside of thesphere, the both spheres having a common center point CP. Then, thesecond cavities 35 are considered to be formed in the region outside ofthe imaginary sphere of radius d2. In other words, the second cavities35 are formed spaced apart from the point CP in a way to surround theimaginary sphere.

Referring to FIGS. 7 and 8, it can be seen that the second cavities 35take a linear shape, as compared with the first cavities 34. This isbecause the resin 40 surrounding the second cavities 35 is reflowed whenthe primary resin particle 45 is heat-treated, and thus the shape of thefirst cavities 34 is changed into a rather flat form.

The secondary resin particle 50 is provided with fine concave portionson the surface 48 thereof which are formed by the second cavities 35.That is, the first cavities 34 are changed into the second cavities 35having a flat form during the heat-treatment process, and the secondaryresin particle 50 is shrunk by a volume difference between the first andsecond cavities 34 and 35 such that the fine concave portions are formedon the surface 48 of the secondary resin particle 50. Since the fineconcave portions are randomly formed on the surface 48 of the resinparticle 50 in enormous number, they may appear to be wrinkles.

FIG. 9 is a perspective view showing the conductive particle of FIG. 6.

Referring to FIG. 9, the conductive particle 100 includes the secondaryresin particle 50 and the conductive layer 70 that surrounds thesecondary resin particle 50. In this embodiment, the conductive layer 70is formed on the surface of the secondary resin particle 50 usingplating technique, so that the concave portions (wrinkles) on theconductive layer 70 can remain on the surface of the conductive particle100.

FIG. 10 is a perspective view showing a liquid crystal display 300according to an embodiment of the present invention. FIG. 11 is asectional view taken along the line I-I′ in FIG. 10.

Referring to FIG. 10, the liquid crystal display 300 includes a liquidcrystal display panel 130 displaying an image in response to a pixelvoltage, a gate driver 170 electrically connected to the liquid crystaldisplay panel 130 to supply a gate signal to the liquid crystal displaypanel 130, and a data driver 230 electrically connected to the liquidcrystal display panel 130 to supply a data signal to the liquid crystaldisplay panel 130.

The liquid crystal display panel 130 includes an array substrate 120, acolor filter substrate 110 facing the array substrate, and a liquidcrystal layer (not shown) interposed between the array substrate 120 andthe color filter substrate 110.

The array substrate 120 is formed of a transparent glass substrate onwhich thin film transistors (not shown) are arranged in a matrixconfiguration. Although not illustrated, the array substrate 120includes pixel electrodes electrically connected to the thin filmtransistors. When the gate signal is applied to the thin filmtransistors from the gate driver 170, the thin film transistors areturned on such that a pixel voltage is applied to the pixel electrodesfrom the data driver 230.

The color filter substrate 110 includes a transparent glass substrate onwhich color filters each having a red, green, or blue color are formed.Also, the color filter substrate 110 includes a common electrode (notshown) formed over the color filter substrate 110. When a common voltageis applied to the common electrode, an electric field is formed betweenthe common electrode and the pixel electrode, thereby controllingorientations of the liquid crystals within the liquid crystal layer.

The gate driver 170 includes a gate printed circuit board 150, a firstdriving chip 160, and a first tape carrier package (TCP) 140.

The gate printed circuit board 150 supplies a gate signal to the liquidcrystal display panel 130. The gate printed circuit board 150 iselectrically connected to the liquid crystal display panel 130 throughthe first TCP 140, thereby applying the gate signal generated by thegate printed circuit board 150 to the liquid crystal display panel 130.

The first TCP 140 includes an insulating film having a tape-like shapeand a lead wire formed on the insulating film, and the first drivingchip 160 is mounted on the lead wire. As shown in FIG. 11, the first TCP140 includes a second terminal 145 that is electrically connected to afirst terminal 125 formed on the array substrate 120. Accordingly, thefirst driving chip 160 mounted on the first TCP 140 controls the gatesignal applied to the liquid crystal display panel 130 from the gateprinted circuit board 150, so that the liquid crystal display panel 130can display desired images.

In the present exemplary embodiment, as illustrated in FIG. 11, thefirst TCP 140 is electrically connected to the array substrate 120 bymeans of an anisotropic conductive film 105 disposed between the firstand second terminals 125 and 145. The anisotropic conductive filmincludes the conductive particle 100 shown in FIG. 9.

The data driver 230 includes a data printed circuit board 220, a seconddriving chip 210, and a second TCP 200.

The data printed circuit board 220 supplies a data signal to the liquidcrystal display panel 220. The data printed circuit board 220 iselectrically connected to the liquid crystal display panel 130 throughthe second TCP 200, thereby applying the data signal from the dataprinted circuit board 220 to the liquid crystal display panel 130.

Referring to FIG. 11, the first TCP 140 includes the second terminal 145having a metallic material, and the array substrate 120 includes thefirst terminal 125 having a transparent conductive material such asindium tin oxide or indium zinc oxide.

The anisotropic conductive film 105 is interposed between the first andsecond terminals 125 and 145. The anisotropic conductive film 105includes an adhesive resin 103 and the conductive particle 100 dispersedinside the adhesive resin.

The adhesive resin 103 can be cured by heat or light. Thus, when theanisotropic conductive film is compressed, the conductive particle 100therein is prevented from being returned into its original shape by thecured adhesive resin. In other words, the adhesive resin 103 is cured byheat or light while the conductive particle 100 is being compressed, andthus the conductive particle 100 remains in the compressed state by thecured adhesive resin 103.

When compressing the anisotropic conductive film 105 disposed betweenthe first and second terminals 125 and 145, the conductive layer 70formed on the surface of the conductive particle 100 within theanisotropic film is substantially simultaneously contacted to both thefirst and second terminals 125 and 145. Thus, the first terminal 125 andthe second terminal 145 can be electrically connected to each other.

FIGS. 12A and 12B are enlarged views the portion at which the liquidcrystal display panel and the gate driver are bonded to each other.

Referring to FIG. 12A, the conductive particle 100 is interposed betweenthe first terminal 125 and the second terminal 145 and includes a numberof conductive particles. For illustrative purpose, FIG. 12A shows afirst conductive particle 100 a, a second conductive particle 100 b anda third conductive particle 100 c, which have different diameters fromeach other.

Especially, the first conductive particle 100 a has a diameter smallerthan that of the second conductive particle 100 b, and the secondconductive particle 100 b has a diameter smaller than that of the thirdconductive particle 100 c. Accordingly, when the first, second and thirdconductive particles 100 a, 100 b and 100 c are compressed between thefirst and second terminals 125 and 145, the compressed first, second andthird conductive particles come to have width W1, W2 and W3 respectivelywhere W1 is smaller than W2 and W2 is smaller than W3, as shown FIG.12A.

As previously mentioned, the conductive particle 100 includes the secondcavities 35 formed therein (see FIG. 8B). Due to the second cavities 35formed in the conductive particle 100, the conductive particle 100 canreadily absorb an external pressure, thereby providing an improvedmalleability to the conductive particle 100.

In particular, where the conductive particles 100 have differentdiameters from each other such as in the first, second and thirdconductive particles 100 a, 100 b, and 100 c, the higher externalpressure will be applied to the conductive particle, the higher diameterit has. For example, the applied external pressure will become larger inthe order of the first, second and third conductive particles. However,the largest third conductive particle 100 c can readily absorb thepressure as much, thereby enabling to mitigate the pressure beingtransmitted to the first terminal 125 or the second terminal 145.

If the pressure is not absorbed by the third conductive particle 100 cand thus transmitted to the first terminal 125 through the thirdconductive particle 100 c, the first terminal 125 including thetransparent conductive layer or a thin film layer formed under the firstterminal 125 may be damaged. However, according to the present exemplaryembodiment, since the third conductive particle 100 c is designed tosufficiently absorb the pressure, the first terminal 125 or the thinfilm layer under the first terminal 125 can not be easily damaged fromthe external pressure.

Referring to FIG. 12B, the second terminal 145 is inclined with respectto the first terminal 125 at an inclination angle (θ). Further, theconductive particles 100 disposed between the first and second terminals125 and 145, i.e., fourth, fifth and sixth conductive particles 100 d,100 e and 100 f have a same diameter before compressed.

Therefore, when the inclined second terminal 145 compresses the fourth,fifth and sixth conductive particles 100 d, 100 e and 100 f, differentpressures are applied to the respective conductive particles dependingupon their relative positions. That is, the pressure applied to thefourth conductive particle 100 d is greater than the pressure applied tothe fifth conductive particle 100 e, and the pressure applied to thefifth conductive particle 100 e is greater than the pressure applied tothe sixth conductive particle 100 f. Thus, the fourth conductiveparticle 100 d has a height H1 smaller than a second height H2 of thefifth conductive particle 100 e, and the sixth conductive particle 100 fhas a third height H3 larger than the second height H2 of the fifthconductive particle 100 e.

Accordingly, although the different pressures are applied to the fourth,fifth and sixth conductive particles 100 d, 100 e and 100 f, theconductive particles 100 can easily absorb the pressure applied theretodue to the second cavities formed in the particles such that theconductive particle 100 can be sufficiently and appropriately malleablebetween the first and second terminals 125 and 145.

Further, although the fourth conductive particle 100 d is more stronglycompressed, rather than the fifth and sixth conductive particles 100 eand 100 f, the cavities formed therein can absorb a large amount of thepressure. Thus, the pressure applied to the fourth conductive particle100 d cannot be easily transmitted to the first terminal 125 or thesecond terminal 145 to the extent to damage the first terminal 125 orthe thin film layer formed under the first terminal 145.

As described above, the cavities formed inside the conductive particle(resin particle) provides an improved malleability to the anisotropicconductive adhesive containing the conductive particles. Thus, when theanisotropic conductive adhesive is compressed, the conductive particlecan readily absorb the external compressive pressure. Thus, although theexternal pressure is applied to the anisotropic conductive adhesiveinterposed between the first and second terminals, the first terminal orthe second terminal can be prevented from being damaged, due to thepressure absorption by the conductive particles, i.e., by the cavitiesformed therein.

Although the exemplary embodiments have been disclosed here, it isunderstood that the present invention is not limited to these exemplaryembodiments, but various changes and modifications can be made by oneordinary skilled in the art within the spirit and scope of the presentinvention as defined by the appended claims.

In addition, many modifications can be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodimentsdisclosed as the best mode contemplated for carrying out this invention,but that the invention will include all embodiments falling within thescope of the appended claims. Moreover, the use of the terms first,second, etc., do not denote any order or importance, but rather theterms first, second, etc., are used to distinguish one element fromanother. Furthermore, the use of the terms a, an, etc., do not denote alimitation of quantity, but rather denote the presence of at least oneof the referenced item.

1. A method of manufacturing a conductive particle, comprising: mixing aresin with a first reactant to form a particle; removing the firstreactant from the particle using a second reactant to form a cavity inthe particle; heat-treating the particle; and forming a conductive layersurrounding the particle.
 2. The method of claim 1, wherein the volumeof the cavity is reduced while heat-treating the particle such that thesurface of the particle is partially concave.
 3. The method of claim 1,wherein the first reactant comprises calcium carbonate, and the secondreactant comprises hydrochloric acid.
 4. The method of claim 1, furthercomprising, prior to removing the first reactant, reacting the firstreactant with a third reactant to make a surface of the first reactantinto a hydrophobic state.
 5. The method of claim 4, wherein the firstreactant comprises calcium carbonate, and the third reactant comprisesat least one of ethanol and stearic acid.
 6. The method of claim 1,wherein the second reactant moves from a surface of the particle to acenter of the particle while removing the first reactant, the cavity israndomly formed in a region from a surface of the particle to apredetermined depth, and a malleability of the particle is improved asthe predetermined depth increases.
 7. The method of claim 6, wherein themalleability of the particle is more improved by about 10 percentscompared with a case where the cavity is not formed in the particle whenthe predetermined depth is about 0.1 times more than a diameter of theparticle.
 8. A method of manufacturing a display apparatus, comprising:preparing a display panel on which a first terminal is formed and adriver on which a second terminal is formed; forming a conductiveparticle; forming an anisotropic conductive adhesive having theconductive particle on at least one of the first terminal and the secondterminal; and positioning the first terminal and the second terminal toface each other while interposing the anisotropic conductive adhesivebetween the first and second terminals and compressing the first andsecond terminals to be electrically connected to each other, wherein theconductive particle is formed by: mixing a resin with a first reactantto form a particle; removing the first reactant from the particle usinga second reactant to form a cavity in the particle; heat-treating theparticle; and forming a conductive layer surrounding the particle. 9.The method of claim 8, wherein a volume of the cavity is reduced whileheat-treating the particle such that a surface of the particle ispartially concave.
 10. The method of claim 8, wherein the first reactantcomprises calcium carbonate, and the second reactant compriseshydrochloric acid.
 11. The method of claim 8, further comprising, priorto removing the first reactant, reacting the first reactant with a thirdreactant to make a surface of the first reactant in a hydrophobic state.12. The method of claim 11, wherein the first reactant comprises calciumcarbonate, and the third reactant comprises at least one of ethanol andstearic acid
 13. The method of claim 8, wherein the second reactantmoves from a surface of the particle to a center of the particle whileremoving the first reactant, the cavity is randomly formed in a regionfrom a surface of the particle to a predetermined depth, and amalleability of the particle is improved as the predetermined depthincreases.
 14. The method of claim 13, wherein the malleability of theparticle is more improved by about 10 percents compared with a casewhere the cavity is not formed in the particle when the predetermineddepth is about 0.1 times more than a diameter of the particle.
 15. Ananisotropic conductive adhesive comprising: an adhesive; and aconductive particle dispersed in the adhesive, wherein the conductiveparticle comprises: a particle that is provided with a cavity formedtherein to have a concave portion at a surface thereof; and a conductivelayer surrounding the particle.
 16. The anisotropic conductive adhesiveof claim 15, wherein the cavity is formed at the surface of the particleand in the particle.
 17. The anisotropic conductive adhesive of claim15, wherein the adhesive is cured by at least one of heat and light. 18.The anisotropic conductive adhesive of claim 15, wherein the particlecomprises a reactant dispersed therein.
 19. The anisotropic conductiveadhesive of claim 18, wherein the reactant is partially removed from theparticle to form the cavity.